RVDTs are non contact transducers that incorporate proprietary rotor and coil designs to measure angular position.
Their basic construction eliminates items such as slip rings, rotor windings, contact brushes or wipers that degrade over time and impair reliability. At the same time the coil design achieves extraordinarily high output and low noise.
The coil design comprises a primary and two secondary windings all placed in the stator. There are no windings in the rotor. The secondary windings act as pickup coils detecting the flux change caused by rotation of the rotor. The stator core is a lamination stack of highly permeable magnetic alloy material and the rotor is made of the same material. A very small air gap separates these components. This combination provides for an “all-iron” flux path that provides for very high efficiency resulting in a very high signal to noise ratio and a very low temperature coefficient of scale factor.